Optimizing the Caloric Properties of Cu-Doped Ni-Mn-Ga Alloys.

With the purpose to optimize the functional properties of Heusler alloys for their use in solid-state refrigeration, the characteristics of the martensitic and magnetic transitions undergone by NiMnGaCu ( = 3-11) alloys have been studied. The results reveal that, for a Cu content of = 5.5-7.

Author Correction: Temperature Chaos, Memory Effect, and Domain Fluctuations in the Spiral Antiferromagnet Dy.

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Temperature Chaos, Memory Effect, and Domain Fluctuations in the Spiral Antiferromagnet Dy.

The spiral antiferromagnetic phase of polycrystalline dysprosium between 140 K and the Néel temperature at 178 K and its domain wall (DW) dynamics were investigated using high-resolution ultrasonic spectroscopy. Two kinetic processes of quasi-static DW motion occur under non-isothermal and isothermal conditions. A "fast" process is proportional to the rate of the temperature change and results in a new category of anelastic phenomena: magnetic transient ultrasonic internal friction (IF).

On the Effect of Hydrogen on the Low-Temperature Elastic and Anelastic Properties of Ni-Ti-Based Alloys.

Linear and non-linear internal friction and the effective Young's modulus of a NiTi alloy have been studied after different heat treatments, affecting hydrogen content, over wide ranges of temperatures (13-300 K) and strain amplitudes (10-10) at frequencies near 90 kHz. It has been shown that the contamination of the alloy by hydrogen strongly affects the internal friction and Young's modulus of the martensitic phase. Presence of hydrogen gives rise to a non-relaxation internal friction maximum due to a competition of two different temperature-dependent processes.

Non-Isothermal Kinetic Analysis of the Crystallization of Metallic Glasses Using the Master Curve Method.

The non-isothermal transformation rate curves of metallic glasses are analyzed with the Master Curve method grounded in the Kolmogorov-Johnson-Mehl-Avrami theory. The method is applied to the study of two different metallic glasses determining the activation energy of the transformation and the experimental kinetic function that is analyzed using Avrami kinetics. The analysis of the crystallization of CuTiZrNi₈Si₁ metallic glassy powders gives E = 3.